From: David Howells <dhowells@redhat.com>
To: Jens Axboe <axboe@kernel.dk>, Al Viro <viro@zeniv.linux.org.uk>,
Christoph Hellwig <hch@infradead.org>
Cc: David Howells <dhowells@redhat.com>,
Matthew Wilcox <willy@infradead.org>, Jan Kara <jack@suse.cz>,
Jeff Layton <jlayton@kernel.org>,
David Hildenbrand <david@redhat.com>,
Jason Gunthorpe <jgg@nvidia.com>,
Logan Gunthorpe <logang@deltatee.com>,
Hillf Danton <hdanton@sina.com>,
linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Christoph Hellwig <hch@lst.de>,
John Hubbard <jhubbard@nvidia.com>
Subject: [PATCH v14 16/17] block: Convert bio_iov_iter_get_pages to use iov_iter_extract_pages
Date: Tue, 14 Feb 2023 17:13:29 +0000 [thread overview]
Message-ID: <20230214171330.2722188-17-dhowells@redhat.com> (raw)
In-Reply-To: <20230214171330.2722188-1-dhowells@redhat.com>
This will pin pages or leave them unaltered rather than getting a ref on
them as appropriate to the iterator.
The pages need to be pinned for DIO rather than having refs taken on them to
prevent VM copy-on-write from malfunctioning during a concurrent fork() (the
result of the I/O could otherwise end up being affected by/visible to the
child process).
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
cc: Al Viro <viro@zeniv.linux.org.uk>
cc: Jens Axboe <axboe@kernel.dk>
cc: Jan Kara <jack@suse.cz>
cc: Matthew Wilcox <willy@infradead.org>
cc: Logan Gunthorpe <logang@deltatee.com>
cc: linux-block@vger.kernel.org
---
Notes:
ver #10)
- Drop bio_set_cleanup_mode(), open coding it instead.
ver #8)
- Split the patch up a bit [hch].
- We should only be using pinned/non-pinned pages and not ref'd pages,
so adjust the comments appropriately.
ver #7)
- Don't treat BIO_PAGE_REFFED/PINNED as being the same as FOLL_GET/PIN.
ver #5)
- Transcribe the FOLL_* flags returned by iov_iter_extract_pages() to
BIO_* flags and got rid of bi_cleanup_mode.
- Replaced BIO_NO_PAGE_REF to BIO_PAGE_REFFED in the preceding patch.
block/bio.c | 23 ++++++++++++-----------
1 file changed, 12 insertions(+), 11 deletions(-)
diff --git a/block/bio.c b/block/bio.c
index 547e38883934..fc57f0aa098e 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -1212,7 +1212,7 @@ static int bio_iov_add_page(struct bio *bio, struct page *page,
}
if (same_page)
- put_page(page);
+ bio_release_page(bio, page);
return 0;
}
@@ -1226,7 +1226,7 @@ static int bio_iov_add_zone_append_page(struct bio *bio, struct page *page,
queue_max_zone_append_sectors(q), &same_page) != len)
return -EINVAL;
if (same_page)
- put_page(page);
+ bio_release_page(bio, page);
return 0;
}
@@ -1237,10 +1237,10 @@ static int bio_iov_add_zone_append_page(struct bio *bio, struct page *page,
* @bio: bio to add pages to
* @iter: iov iterator describing the region to be mapped
*
- * Pins pages from *iter and appends them to @bio's bvec array. The
- * pages will have to be released using put_page() when done.
- * For multi-segment *iter, this function only adds pages from the
- * next non-empty segment of the iov iterator.
+ * Extracts pages from *iter and appends them to @bio's bvec array. The pages
+ * will have to be cleaned up in the way indicated by the BIO_PAGE_PINNED flag.
+ * For a multi-segment *iter, this function only adds pages from the next
+ * non-empty segment of the iov iterator.
*/
static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
{
@@ -1272,9 +1272,9 @@ static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
* result to ensure the bio's total size is correct. The remainder of
* the iov data will be picked up in the next bio iteration.
*/
- size = iov_iter_get_pages(iter, pages,
- UINT_MAX - bio->bi_iter.bi_size,
- nr_pages, &offset, extraction_flags);
+ size = iov_iter_extract_pages(iter, &pages,
+ UINT_MAX - bio->bi_iter.bi_size,
+ nr_pages, extraction_flags, &offset);
if (unlikely(size <= 0))
return size ? size : -EFAULT;
@@ -1307,7 +1307,7 @@ static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
iov_iter_revert(iter, left);
out:
while (i < nr_pages)
- put_page(pages[i++]);
+ bio_release_page(bio, pages[i++]);
return ret;
}
@@ -1342,7 +1342,8 @@ int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
return 0;
}
- bio_set_flag(bio, BIO_PAGE_REFFED);
+ if (iov_iter_extract_will_pin(iter))
+ bio_set_flag(bio, BIO_PAGE_PINNED);
do {
ret = __bio_iov_iter_get_pages(bio, iter);
} while (!ret && iov_iter_count(iter) && !bio_full(bio, 0));
next prev parent reply other threads:[~2023-02-14 17:16 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-14 17:13 [PATCH v14 00/17] iov_iter: Improve page extraction (pin or just list) David Howells
2023-02-14 17:13 ` [PATCH v14 01/17] mm: Pass info, not iter, into filemap_get_pages() David Howells
2023-02-14 17:13 ` [PATCH v14 02/17] splice: Add a func to do a splice from a buffered file without ITER_PIPE David Howells
2023-02-18 2:41 ` Ming Lei
2023-02-18 9:25 ` David Howells
2023-02-14 17:13 ` [PATCH v14 03/17] splice: Add a func to do a splice from an O_DIRECT " David Howells
2023-02-14 17:13 ` [PATCH v14 04/17] shmem: Implement splice-read David Howells
2023-02-14 17:13 ` [PATCH v14 05/17] overlayfs: " David Howells
2023-02-15 14:21 ` Miklos Szeredi
2023-02-15 15:03 ` David Howells
2023-02-15 15:32 ` Miklos Szeredi
2023-02-15 15:40 ` [PATCH v15 " David Howells
2023-02-15 15:50 ` Miklos Szeredi
2023-02-15 15:53 ` Matthew Wilcox
2023-02-15 16:38 ` Christoph Hellwig
2023-02-15 16:40 ` Miklos Szeredi
2023-02-15 15:58 ` David Howells
2023-02-14 17:13 ` [PATCH v14 06/17] coda: " David Howells
2023-02-14 18:04 ` Jan Harkes
2023-02-14 17:13 ` [PATCH v14 07/17] tty, proc, kernfs, random: Use direct_splice_read() David Howells
2023-02-14 17:13 ` [PATCH v14 08/17] splice: Do splice read from a file without using ITER_PIPE David Howells
2023-02-17 8:22 ` Ming Lei
2023-02-17 9:18 ` Ming Lei
2023-02-17 20:39 ` Alexander Egorenkov
2023-02-17 20:59 ` egorenar
2023-02-17 21:24 ` David Howells
2023-02-17 21:16 ` David Howells
2023-02-17 21:47 ` David Howells
2023-02-18 8:29 ` Alexander Egorenkov
2023-02-18 9:18 ` David Howells
2023-02-14 17:13 ` [PATCH v14 09/17] iov_iter: Kill ITER_PIPE David Howells
2023-02-14 17:13 ` [PATCH v14 10/17] iov_iter: Define flags to qualify page extraction David Howells
2023-02-14 17:13 ` [PATCH v14 11/17] iov_iter: Add a function to extract a page list from an iterator David Howells
2023-02-14 17:13 ` [PATCH v14 12/17] iomap: Don't get an reference on ZERO_PAGE for direct I/O block zeroing David Howells
2023-02-14 17:13 ` [PATCH v14 13/17] block: Fix bio_flagged() so that gcc can better optimise it David Howells
2023-02-14 17:13 ` [PATCH v14 14/17] block: Replace BIO_NO_PAGE_REF with BIO_PAGE_REFFED with inverted logic David Howells
2023-02-14 17:13 ` [PATCH v14 15/17] block: Add BIO_PAGE_PINNED and associated infrastructure David Howells
2023-02-14 17:13 ` David Howells [this message]
2023-02-14 17:13 ` [PATCH v14 17/17] block: convert bio_map_user_iov to use iov_iter_extract_pages David Howells
2023-02-14 22:56 ` [PATCH v14 00/17] iov_iter: Improve page extraction (pin or just list) David Howells
2023-02-14 23:05 ` Jens Axboe
2023-02-15 8:07 ` David Howells
2023-02-15 14:23 ` Christoph Hellwig
2023-02-15 14:38 ` Christoph Hellwig
2023-02-15 15:43 ` David Howells
2023-02-15 8:20 ` David Howells
2023-02-14 23:01 ` David Howells
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